Stacked Munitions Launcher and Method Therefor

ABSTRACT

A system for launching a plurality of projectiles from a single launch tube is disclosed. In the illustrative embodiment, the system uses an electromagnetic catapult to sequentially throw a first projectile and a second projectile. The first projectile is thrown while the second projectile is temporarily restrained within the launch tube.

CROSS REFERENCE TO RELATED APPLICATIONS

The underlying concepts, but not necessarily the language, of the following cases are incorporated by reference:

(1) U.S. patent application Ser. No. 10/899,234, filed 26 Jul. 2004;

(2) U.S. patent application Ser. No. 11/278,988, filed 7 Apr., 2006;

(3) U.S. patent application Ser. No. 11/428,697, filed 5 Jul., 2006;

(4) U.S. patent application Ser. No. 11/535,480, filed 26 Sept., 2006;and

(5) U.S. patent application Ser. No. 11/773,146, filed 3 Jul., 2007.If there are any contradictions or inconsistencies in language between this application and one or more of the cases that have been incorporated by reference that might affect the interpretation of the claims in this case, the claims in this case should be interpreted to be consistent with the language in this case.

FIELD OF THE INVENTION

The present invention relates to munitions in general, and, more particularly, to munition launchers.

BACKGROUND OF THE INVENTION

Projectiles, such as missiles, mortar rounds, countermeasure devices, and the like, are often stored, shipped, and carried to their point of deployment in canisters. Among other things, a canister protects a projectile from harsh environmental conditions. A typical canister comprises a launch tube that guides the projectile as it is launched, much like the launch tube of a gun. At deployment, the canister may be secured in a launch apparatus and the projectile is propelled from its canister, typically by means of a chemical propellant.

In order to avoid damage during transport, a projectile is usually secured within its canister by attaching it to the base plate of the canister by means of a mechanical release restraint. The restraint is actuated to release the projectile and enable its propulsion from the canister at launch. Commonly used restraints include explosive bolts, marmon clamps, bullet jackets, and shape charges. Once the projectile has been launched, its canister is replaced in the launch apparatus by a fresh canister in preparation for the launch of another projectile.

Often, it is desirable to be able to launch many projectiles within a short period of time, such as for the deployment of countermeasure devices. Countermeasure systems are employed by military vessels to confuse or otherwise frustrate the targeting systems of an approaching missile or similar threat. Modern missiles have targeting systems that incorporate sophisticated sensor platforms that are capable of sensing target signature information across a spectrum of signal types (e.g., radar, acoustic, thermal, etc.). An effective countermeasure system, therefore, must be capable of rapidly deploying a plurality of countermeasure devices (e.g., flares, chaff, acoustic emitters, IR emitters, etc.) to present a false image (i.e., decoy) that closely mimics the multispectral signature, shape, and behavior of the actual vessel.

To achieve a high aggregate firing rate, conventional multiple-projectile launch systems constitute multiple individual projectile launchers or launch tubes, each of which propels a single projectile. FIG. 1 depicts a schematic diagram of an exemplary prior art multiple-projectile launcher. Countermeasure launcher 100 comprises multiple launch tubes that are held in a pre-arranged configuration by a platform that is attached to the deck of a warship. The launch tubes are suitable for launching countermeasure payloads using a chemical-propellant, such as black-powder explosives. The launch tubes are pre-loaded with an array of countermeasure devices, depending on the characteristics of the vessel on which they reside.

Conventional countermeasure launchers have certain drawbacks that limit their effectiveness, however.

First, such systems offer limited flexibility in projectile placement. Specifically, these conventional systems typically launch their projectiles at fixed positions and fixed launch angles. Furthermore, the propulsive force from the chemical propellant of each missile is not controllable. As a consequence, effective decoy placement requires that a vessel undergo complicated maneuvers prior to and after launch.

Secondly, the use of a chemical-propellant creates a characteristic signature that has thermal, aural, and visual aspects. In particular, the signature may include a thermal bloom, a cloud of smoke, noise, a thermal trail, and/or a smoke trail. In most cases, the thermal bloom heats the area immediate to the launch area, which results in a residual local thermal signature that can act as a beacon for an incoming threat.

Thirdly, after launch, the launcher must be cleaned and reloaded. In the case of a countermeasure launcher, this renders the vessel relatively more vulnerable to attack. In the case of a multi-cell offensive weapon, this renders the launcher impotent for a period of time.

Finally, as the number of launchers or launch tubes increases, the size of the launch system grows and contributes significantly to deck clutter. This also increases the complexity and cost of the launch system.

Electromagnetic launchers have been developed as an alternative to chemical propellant launchers. Electromagnetic launchers mitigate some of the disadvantages associated with the use of chemical propellants; however, prior art electromagnetic launchers are limited to the launch of a single projectile per launch tube. As a result, an array of electromagnetic launchers must used to provide a launch system capable of the rapid launch of a plurality of projectiles. An electromagnetic propulsion system requires greater infrastructure and is more complex than a chemical propellant propulsion system, which exacerbates the problems associated with deck clutter and overall system cost. There exists a need, therefore, for a multi-projectile launch system that avoids or mitigates some or all of the problems associated with prior-art multiple projectile launch systems.

SUMMARY OF THE INVENTION

The present invention provides a launcher for propelling multiple projectiles without some of the costs and disadvantages associated with launchers known in the prior art.

An embodiment of the present invention comprises an electromagnetic propulsion system for accepting and securing a removable cartridge that contains a plurality of projectiles. The propulsion system comprises a plurality of propulsion coils for generating force to propel each of the plurality of projectiles from the cartridge. In some embodiments, the propulsion system also comprises a propulsion coil for ejecting the cartridge. In some embodiments, the cartridge is immobilized with respect to the propulsion system by a passively-actuated restraint.

In some embodiments, the cartridge comprises a launch tube that contains a plurality of projectiles. Each projectile is individually secured within the launch tube by a passively-actuated restraint. In the absence of electromagnetic force, each restraint substantially immobilizes its respective projectile with respect to the launch tube. In some embodiments, a restraint comprises an electrically-conductive loop that is located on the projectile. In some embodiments, the electrically-conductive loop is located on another structure, such as an armature, that is operatively coupled to the projectile. In some embodiments, the electrically-conductive loop is mechanically coupled to the cartridge.

To launch a projectile, a flow of electric current is generated through a propulsion coil. Mutual inductance between the propulsion coil and a restraint causes the restraint to actuate and release the projectile, thereby enabling motion of the projectile with respect to the cartridge. Mutual inductance between the propulsion coil and the projectile induces a propulsive force on the projectile that ejects the projectile from the launcher. Since only one restraint at a time is actuated, multiple projectiles can be stored and launched from a single launch tube.

In some embodiments, a cartridge is secured within the propulsion system by a passively-actuated restraint. To eject the cartridge from the propulsion system, a flow of electric current is generated through a propulsion coil. Mutual inductance between the propulsion coil and the restraint causes the restraint to actuate and release the cartridge, thereby enabling motion of the cartridge with respect to the propulsion system. Mutual inductance between the propulsion coil and the cartridge induces a propulsive force on the cartridge that ejects the cartridge from the propulsion system. In some embodiments, cartridges are loaded into the propulsion system by an automatic cartridge loader.

A method in accordance with the present invention comprises:

-   -   engaging a cartridge and an electromagnetic propulsion system;         -   wherein the cartridge comprises a tube containing a first             projectile and a second projectile;         -   wherein the electromagnetic propulsion system comprises a             first propulsion coil and a second propulsion coil; and         -   wherein the cartridge locates the first projectile with             respect to the first propulsion coil and the second             projectile with respect to the second propulsion coil when             the cartridge and electromagnetic propulsion system are             engaged;     -   propelling the first projectile from the electromagnetic         propulsion system, wherein the first projectile is propelled by         a first force that is induced by the flow of electric current in         the first propulsion coil; and     -   disengaging the cartridge from the electromagnetic propulsion         system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic diagram of an exemplary prior art multiple-projectile launcher.

FIG. 2 depicts a block diagram of an electromagnetic launch system in accordance with an illustrative embodiment of the present invention.

FIG. 3 depicts the details of method 300 in accordance with the illustrative embodiment.

FIG. 4A depicts a representational view of launcher 202, prior to insertion of cartridge 408 in propulsion system 402, in accordance with the illustrative embodiment of the present invention.

FIG. 4B depicts a cross-sectional view of details of propulsion system 402 in accordance with the illustrative embodiment of the present invention.

FIG. 4C depicts a cross-sectional view of details of cartridge 408 in accordance with the illustrative embodiment of the present invention.

FIG. 5A depicts a representational view of launcher 202, after insertion of cartridge 408 in propulsion system 402, in accordance with the illustrative embodiment of the present invention.

FIG. 5B depicts a cross-sectional view of details of launcher 202 in accordance with the illustrative embodiment of the present invention.

FIG. 6 depicts a top view of details of a conductive loop in accordance with the illustrative embodiment of the present invention.

DETAILED DESCRIPTION

The following terms are defined for use in this Specification, including the appended claims:

-   -   Locate means to place at a certain location.     -   Physically connected means in direct, physical contact and         affixed (e.g., a mirror that is mounted on a linear-motor).     -   Physically coupled means in direct, physical contact, although         not necessarily physically-connected (e.g., a coffee cup resting         on a desktop).     -   Projectile means an object that is fired, thrown, or otherwise         propelled. Examples of projectiles include, without limitation,         artillery shells, mortar rounds, self-propelled missiles,         unmanned aerial vehicles, guided missiles, and countermeasure         devices, such as flares, chaff, acoustic emitters, IR emitters,         and the like.

FIG. 2 depicts a block diagram of an electromagnetic launch system in accordance with an illustrative embodiment of the present invention. Electromagnetic launch system 200 comprises multi-projectile electromagnetic launcher 202 (hereinafter, launcher 202), launch controller 204, weapons control system 206, power system 208, data bus 210, current bus 214, and signal line 212.

Launcher 202 is a system that has the capability to house and expel multiple projectiles upon command. The system expels the projectiles using an electromagnetic catapult. Although in the illustrative embodiment, launcher 202 expels projectiles that comprise countermeasures, it will be clear to those of ordinary skill in the art how to make and use alternative embodiments of the present invention that expel projectiles such as munitions, unmanned vehicles, guided missiles, chaff, flares, acoustic emitters, acoustic sensors, and the like.

Launch controller 204 provides targeting information to launcher 202 prior to launch. Launch controller 204 also provides the directive to initiate a launch of one or more projectiles to power system 208. In some alternative embodiments, such as when launcher 202 expels a guided missile or unmanned vehicle, launch controller 204 also provides targeting and/or course information to launcher 202 and/or the projectile to be expelled. In some embodiments, at least one projectile comprises built-in test electronics. In these embodiments, launch controller receives self-test data from these projectiles. In some embodiments, launcher 202 comprises mechanisms for setting the elevation and azimuth at which a projectile is launched. In some embodiments, launch controller 204 communicates with these mechanisms to control elevation and azimuth.

Weapons control system 206 provides targeting and firing authority to launch controller 204 prior to and during a launch of one or more projectiles.

Power system 208 comprises circuitry that conditions and manages the storage and delivery of power to launcher 202 in response to signals from launch controller 204. Power system 208 controls power generation, scavenging, storage, and delivery prior to, during, and after each launch. Power system 208 also controls the magnitude of the force with which launcher 202 propels each projectile.

Data bus 210 carries targeting and self-test information between launch controller 204 and launcher 202. Signal line 212 connects launch controller 204 to power system 208 and carries the commands that direct power system 208 to initiate and control the launch of a projectile. Current bus 214 carries power from power system 208 to launcher 202.

FIG. 3 depicts the details of method 300 in accordance with the illustrative embodiment. Method 300 depicts operations for launching multiple projectiles using launcher 202. Method 300 is described herein with reference to FIGS. 4A-C, 5A-B, and 6.

FIG. 4A depicts a representational view of launcher 202, prior to insertion of cartridge 408 in propulsion system 402, in accordance with the illustrative embodiment of the present invention. Launcher 202 comprises propulsion system 402 and cartridge 408.

Propulsion system 402 comprises retainer 406 and propulsion coils 404-1, 404-2, and 404-3. Each of propulsion coils 404-1, 404-2, and 404-3 comprises a helical coil of electrical conductor, capable of carrying sufficiently high voltage/amperage to enable sufficient launch power. Each of propulsion coils 404-1, 404-2, and 404-3 generates an electromagnetic field when carrying electric current. Propulsion system 402 accepts, locates, and restrains cartridge 408.

Cartridge 408 comprises a canister for holding, locating, and restraining projectiles 412-1 and 412-2. Cartridge 408 also comprises base plate 410, projectiles 412-1 and 412-2, and restraints 414-1 and 414-2. Restraints 414-1 and 414-2 substantially immobilize projectiles 412-1 and 412-2, respectively, with respect to cartridge 408. Cartridge 408 provides a substantially air-tight environment for the projectiles. In some embodiments, cartridge 408 holds more than two projectiles. In some embodiments, cartridge 408 comprises more than two restraints.

FIG. 4B depicts a cross-sectional view of details of propulsion system 402 in accordance with the illustrative embodiment of the present invention. Propulsion system 402 comprises frame 416, propulsion coils 404, and retainer 406.

Frame 416 provides a rigid structure for holding propulsion coils 404 in well-known fashion.

Retainer 406 includes seat 418 for receiving conductive loop 430-3 when restraint 502 is engaged. As is described below, and with respect to FIG. 5B, retainer 406, conductive loop 430-3, and base plate 410 collectively define restraint 502. When restraint 502 is engaged, retainer 406 receives conductive loop 430-3. This substantially immobilizes base plate 410 (and cartridge 408) with respect to propulsion system 402.

FIG. 4C depicts a cross-sectional view of details of cartridge 408 in accordance with the illustrative embodiment of the present invention. Cartridge 408 comprises base plate 410, launch tube 424, fly-through cover 426, projectiles 412-1 and 412-2, restraints 414-1 and 414-2, and spacers 434.

Base plate 410 is a substantially rigid plate of structural material that is suitable for the development of mutual inductance with propulsion coil 404-3 when the propulsion coil carries electric current. In some embodiments, base plate 410 comprises a coil of electrically conductive wire. In some embodiments, base plate 410 comprises a material having high magnetic permeability, such as Permalloy, nickel, steel, and the like.

Base plate 410 comprises shoulder 438, which locates conductive loop 430-3. Conductive loop 430-3 is a continuous loop of electrically-conductive material that is suitable for the development of a mutual inductance with propulsion coil 404-3 when this coil carries electric current.

Launch tube 424 is a substantially rigid cylinder for housing and guiding launched munitions. Launch tube 424 includes seats 432-1 and 432-2. Seat 432-1 receives conductive loop 430-1 when restraint 414-1 is engaged. In similar fashion, seat 432-2 receives conductive loop 430-2 when restraint 414-2 is engaged.

Launch tube 424, fly-through cover 426, and base plate 410 collectively form a substantially air-tight environment for projectiles 412-1 and 412-2 in well-known fashion.

Projectiles 412-1 and 412-2 (referred to collectively as projectiles 412) are countermeasure devices for providing decoy signals to an incoming threat, such as an approaching enemy missile. Projectile 412-1 comprises warhead 420-1, armature 422-1, and conductive loop 430-1. Although in the illustrative embodiment conductive loops 430-1 and 430-2 are included in projectiles 412-1 and 412-2, it will be clear to one of ordinary skill in the art, after reading this specification, how to make and use alternative embodiments of the present invention wherein conductive loops 430-1 and 430-2 are a part of launch tube 424 rather than projectiles 412. It will also be clear, after reading this specification, how to make and use alternative embodiments of the present invention wherein projectiles 412 comprise any object, or combination of objects, that can be fired, thrown, or otherwise propelled using an electromagnetic propulsion system. Suitable projectiles include, without limitation:

-   -   i. artillery shells; or     -   ii. mortar rounds; or     -   iii. self-propelled missiles; or     -   iv. unmanned vehicles; or     -   v. guided missiles; or     -   vi. countermeasure devices; or     -   vii. any combination of i, ii, iii, iv, v, and vi.

Projectile 412-2 comprises warhead 420-2, armature 422-2, and conductive loop 430-2. Projectiles 412-1 and 412-2 are immobilized with respect to cartridge 408 by restraints 414-1 and 414-2 (referred to collectively as restraints 414), respectively, and are separated from each other and base plate 410 by spacers 434.

Armatures 422-1 and 422-2 (referred to collectively as armatures 422) are suitable for the development of mutual inductance with its respective propulsion coil when the propulsion coil carries electric current. In some embodiments, at least one of armatures 422 comprises a coil of electrically conductive wire. In some embodiments, at least one of armatures 422 comprises a material having high magnetic permeability, such as Permalloy, nickel, steel, and the like.

Armature 422-1 includes shoulder 428-1, which locates conductive loop 430-1. In similar fashion, armature 422-2 includes shoulder 428-2, which locates conductive loop 430-2. Conductive loops 430-1 and 430-2 are continuous loops of electrically-conductive material that are suitable for the development of a mutual inductance with propulsion coils 404-1 and 404-2, respectively, when these coils carry electric current.

Armature 422-1, conductive loop 430-1, and seat 432-1 collectively define restraint 414-1. In similar fashion, armature 422-2, conductive loop 430-2, and seat 432-2 collectively define restraint 414-2.

Method 300 begins with operation 301, wherein cartridge 408 is inserted into, and engages with, propulsion system 402. In some embodiments, cartridge 408 is inserted into propulsion system 402 from the muzzle end. In some embodiments, cartridge 408 is inserted into propulsion system 402 from the breech end. In some embodiments, launcher 202 includes an automatic cartridge loading system for inserting cartridge 408 into propulsion system 402.

FIG. 5A depicts a representational view of launcher 202, after insertion of cartridge 408 in propulsion system 402, in accordance with the illustrative embodiment of the present invention. FIG. 5A depicts launcher 202 in cross-section but, for clarity, without details of its constituent elements. When propulsion system 402 and cartridge 408 are engaged, projectile 412-1, projectile 412-2, and base plate 410 are located with respect to propulsion coil 404-1, propulsion coil 404-2, and propulsion coil 404-3, respectively. Projectile 412-1, projectile 412-2, and base plate 410 are positioned relative to their respective propulsion coils to enable the efficient propulsion of the projectiles and the canister out of launcher 202.

FIG. 5B depicts a cross-sectional view of details of launcher 202 in accordance with the illustrative embodiment of the present invention. FIG. 5 depicts launcher 202 after insertion of cartridge 408 into propulsion system 402. For clarity, the connections to and from power system 208 are not shown in FIG. 5B.

Once they are engaged, restraint 502 immobilizes canister 408 with respect to propulsion system 402. Retainer 406, base plate 410, and conductive loop 430-3 collectively define restraint 502. While restraint 502 is engaged, conductive loop 430-3 is captured by both seats 418 and shoulder 438. Although in the illustrative embodiment conductive loop is included in cartridge 408, it will be clear to one of ordinary skill in the art, after reading this specification, how to make and use alternative embodiments of the present invention wherein conductive loop 430-3 is included in propulsion system 402.

At operation 302, power system 208 energizes propulsion coil 404-1. The flow of electric current in propulsion coil 404-1 generates an electromagnetic field in the region of propulsion coil 404-1.

At operation 303, restraint 414-1 is actuated to enable motion of projectile 412-1 with respect to cartridge 408. Actuation of restraint 414-1 occurs passively as a result of a first force on conductive loop 430-1, which results from a mutual inductance between conductive loop 430-1 and propulsion coil 404-1. This force compresses conductive loop 430-1 into shoulder 428-1 while disengaging it from seat 432-1. In some embodiments, restraint 414-1 is a non-passively actuated restraint, such as a marmon clamp, explosive bolt, and the like.

At operation 304, mutual inductance between armature 422-1 and propulsion coil 404-1 induces a second force on armature 422-1. This second force propels projectile 412-1 through fly-through cover 426 and out of cartridge 408. Once projectile 412-1 is thrown, the flow of electric current in propulsion coil 404-1 can be stopped.

The force with which projectile 412-1 is thrown from launcher 202 is a function of the flow of electric current in propulsion coil 404-1. The ability to vary the propulsive force on projectile 412-1 is an advantage that electromagnetic propulsion affords over other means of propulsion, such as chemical-engines, explosive charges, etc. Electromagnetic propulsion also enables the use of passively-actuated restraints, such as restraints 414.

At operation 305, power system 208 energizes propulsion coil 404-2. The flow of electric current in propulsion coil 404-2 generates an electromagnetic field in the region of propulsion coil 404-2.

At operation 306, restraint 414-2 is actuated to enable motion of projectile 412-2 with respect to cartridge 408. Actuation of restraint 414-2 occurs passively as a result of a first force on conductive loop 430-2, which results from a mutual inductance between conductive loop 430-2 and propulsion coil 404-2. This force compresses conductive loop 430-2 into shoulder 428-2 while disengaging it from seat 432-2. In some embodiments, restraint 414-2 is a non-passively actuated restraint, such as a marmon clamp, explosive bolt, and the like.

At operation 307, mutual inductance between armature 422-2 and propulsion coil 404-2 induces a second force on armature 422-2. This second force propels projectile 412-2 through fly-through cover 426 and out of cartridge 408. Once projectile 412-2 is thrown, the flow of electric current in propulsion coil 404-2 can be stopped.

In some embodiments, power system 208 sequences the flow of electric current in propulsion coils 404-1 and 404-2 to enhance the propulsive force on projectile 412-2. In some embodiments, propulsion system 402 comprises additional propulsion coils to enable the enhancement of propulsive force on each projectile in a cartridge by sequencing current flow between multiple propulsion coils.

At operation 308, power system 208 energizes propulsion coil 404-3. The flow of electric current in propulsion coil 404-3 generates an electromagnetic field in the region of propulsion coil 404-3.

At operation 309, restraint 502 is actuated to enable motion of cartridge 408 with respect to propulsion system 402. Actuation of restraint 502 occurs passively as a result of a first force on conductive loop 430-3, which results from a mutual inductance between conductive loop 430-3 and propulsion coil 404-3. This force compresses conductive loop 430-3 into shoulder 438 while disengaging it from seat 418. In some embodiments, restraint 502 is a non-passively actuated restraint, such as a marmon clamp, explosive bolt, and the like.

At operation 310, mutual inductance between base plate 410 and propulsion coil 404-3 induces a propulsive force on base plate 410. This propulsive force propels cartridge 408 out of propulsion system 402. Once cartridge 408 is thrown, the flow of electric current in propulsion coil 404-3 can be stopped.

FIG. 6 depicts a top view of details of a conductive loop in accordance with the illustrative embodiment of the present invention. Conductive loop 430-i is representative of any of conductive loops 430-1, 430-2, and 430-3. Conductive loop comprises gap 602-i and latch 604-i. The presence of gap 602-i enables conductive loop 430-i to compress when a compressive force is applied to it. Latch 604-i enables conductive loop 430-i to remain compressed even after the removal of this force.

Latch 604-i comprises jaws 606-i and 608-i. When conductive loop 430-i is compressed in response to the flow of electric current in a propulsion coil, jaws 606-i and 608-i engage to keep conductive loop 430-i from expanding once the flow of electric current stops. Conductive loop 430-i, therefore, is kept in its compressed state even after the removal of the force that acts upon it. Once latch 604-i is engaged, it must be manually disengaged. It should be noted that latch 604-i, as depicted, is only one of many suitable latch designs. In some embodiments, springs are used to ensure that latch 604-i remains engaged throughout the actuation of a restraint. It will be clear to those skilled in the art, after reading this specification, how to specify, make, and use latch 604-i.

It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims. 

1. A method comprising: engaging a cartridge and an electromagnetic propulsion system, wherein the cartridge comprises a tube containing a first projectile and a second projectile, and wherein the electromagnetic propulsion system comprises a first propulsion coil and a second propulsion coil, and wherein the cartridge locates the first projectile with respect to the first propulsion coil and the second projectile with respect to the second propulsion coil when the cartridge and electromagnetic propulsion system are engaged; propelling the first projectile from the electromagnetic propulsion system, wherein the first projectile is propelled by a first force that is induced by the flow of electric current in the first propulsion coil; and disengaging the cartridge from the electromagnetic propulsion system.
 2. The method of claim 1 wherein the flow of electric current in the first propulsion coil generates a first electromagnetic field, and wherein the first force is induced by coupling the first electromagnetic field and a first armature that is operatively coupled to the first projectile.
 3. The method of claim 1 wherein the flow of electric current in the first propulsion coil generates a first electromagnetic field, and wherein the first force is induced by coupling the first electromagnetic field and the first projectile.
 4. The method of claim 1 further comprising propelling the second projectile from the electromagnetic propulsion system, wherein the second projectile is propelled by a second force that is induced by the flow of electric current in the second propulsion coil.
 5. The method of claim 1 further comprising substantially immobilizing the second projectile with respect to the cartridge.
 6. The method of claim 1 wherein disengaging the cartridge from the electromagnetic propulsion system comprises propelling the cartridge from the electromagnetic propulsion system, and wherein the cartridge is propelled by a third force that is induced by a third electromagnetic field.
 7. The method of claim 1 wherein engaging the cartridge and the electromagnetic propulsion system comprises engaging a restraint that immobilizes the cartridge with respect to the electromagnetic propulsion system.
 8. The method of claim 7 wherein disengaging the cartridge from the electromagnetic propulsion system comprises: disengaging the restraint to enable motion of the cartridge from the electromagnetic propulsion system; and propelling the cartridge from the electromagnetic propulsion system, wherein the cartridge is propelled by a third force that is induced by the flow of electric current in a third propulsion coil of the electromagnetic propulsion system.
 9. An apparatus comprising a cartridge for simultaneously locating a first projectile and a second projectile in an electromagnetic propulsion system, wherein the cartridge is physically-adapted to demountably engage with the electromagnetic propulsion system.
 10. The apparatus of claim 9 further comprising the electromagnetic propulsion system.
 11. The apparatus of claim 10 wherein the electromagnetic propulsion system has a first propulsion coil and a second propulsion coil, and wherein the cartridge locates the first projectile with respect to the first propulsion coil, and further wherein the cartridge locates the second projectile with respect to the second propulsion coil.
 12. The apparatus of claim 9 further comprising the first projectile and the second projectile.
 13. The apparatus of claim 9 wherein the cartridge comprises a first restraint for immobilizing the first projectile with respect to the cartridge and a second restraint for immobilizing the second projectile with respect to the cartridge.
 14. The apparatus of claim 13 wherein the first restraint is physically-adapted to enable motion of the first projectile with respect to the cartridge in the presence of a first electromagnetic field.
 15. The apparatus of claim 13 wherein the second restraint is physically-adapted to enable motion of the second projectile with respect to the cartridge in the presence of a second electromagnetic field.
 16. An apparatus comprising: a first projectile; a second projectile; a cartridge for containing the first projectile and the second projectile, wherein the cartridge comprises a first physical-adaptation for engaging an electromagnetic propulsion system, and wherein the cartridge has a longitudinal axis, and further wherein the first projectile and second projectile are arranged along the longitudinal axis.
 17. The apparatus of claim 16 wherein the first physical adaptation comprises a first restraint for demountably engaging the electromagnetic propulsion system to substantially immobilize the cartridge with respect to the electromagnetic propulsion system.
 18. The apparatus of claim 16 further comprising the electromagnetic propulsion system.
 19. The apparatus of claim 18 wherein the electromagnetic propulsion system comprises a first propulsion coil, and further wherein a flow of electric current in the first propulsion coil induces a force on the first armature that propels the first projectile.
 20. The apparatus of claim 18 wherein the first projectile comprises a first armature, and wherein the electromagnetic propulsion system comprises a first propulsion coil, and further wherein a flow of electric current in the first propulsion coil induces a force on the first armature that propels the first projectile.
 21. The apparatus of claim 16 further comprising a first restraint for substantially immobilizing the first projectile with respect to the cartridge and a second restraint for substantially immobilizing the second projectile with respect to the cartridge.
 22. The apparatus of claim 21 wherein the electromagnetic propulsion system comprises a first propulsion coil, and further wherein a flow of electric current in the first propulsion coil: (1) induces a first force on the first restraint that enables motion of the first projectile with respect to the cartridge, and (2) induces a second force that propels the first projectile. 